I'm brewing my Black Pearl Porter today and I'm about to move the batch to the burner in the garage. It is way to cold outside to run a garden hose to my wort chiller so I was wondering if anyone has had luck/experience setting the brew pot out in the frigid cold to cool down.

I think cheesefood and jim are right... I've tried the air temp thing when I found that my chiller had a hole in it (from freezing). Even at those temps it's gonna take a long time-- heat transfer is a lot slower to air than it is to water.

I've brewed outside in sub-zero weather and then put the brewpot in the snow. This, however, took a bit of work.

I have to pack the snow against the brewpot really, really well, and repack it every few minutes. And I stir often. It will work, if you keep at the snow and stirring. I can get my five-gallon batch down to pitching temp in 25-35 minutes usually. Be careful: the brewpot will sink through the snow and rest on the frozen ground (not a bad thing). But watch out that the the surrounding snow doesn't flip the pot's lid.

The lesson I learned: the cold air alone won't do it.

I did three batches using the snowbank wort chiller (since I didn't want to mess with hoses in these temps). Well, I gave in and got an immersion chiller. I'd rather haul in a pot of hot sub-boiling wort and use the immersion chiller at the kitchen sink. Still, though, there is something about putting on the Carhartt "wind bag" and brewing under the stars.